TWI659622B - A system for improving received signal quality - Google Patents

Abstract

A system for improving the quality of a received signal includes: a first antenna for receiving a signal; a first frequency band duplexer coupled to the first antenna; a first receiving path selection circuit connected to the first frequency band The duplexer provides a first path and a second path; and a control circuit connecting the first path and the second path; wherein the control circuit controls the first receiving path selection circuit to obtain the first path And each received signal parameter of the second path, the control circuit determines a receiving path according to each received signal parameter of the first path and the second path, and the receiving path is one of the first path and the second path One, and the receiving path has the best received signal parameters.

Description

   System for improving received signal quality   

The invention relates to a system for improving the quality of received signals, in particular to a system for improving the quality of received signals.

All wireless mobile devices on the market must pass the test of the radiation performance of the whole machine, and this test focuses on the transmission power and receiving sensitivity to measure the radiation performance of the wireless mobile device, and the quality of the received signal is the impact Important factors for users using wireless mobile devices.

The system for improving the quality of the received signal proposed by the present invention can select different paths to obtain better parameters of the received signal, and at the same time increase the power gain, so as to effectively improve the quality of the received signal.

The present invention provides a system for improving the quality of a received signal, including: a first antenna for receiving a signal; a first frequency band duplexer coupled to the first antenna; a first receiving path selection circuit connected to the first antenna; The first frequency band duplexer provides a first path and a second path; and a control circuit connecting the first path and the second path; wherein the control circuit controls the first receiving path selection circuit to obtain the first path and the second path; Each received signal parameter of the first path and the second path, the control circuit determines a receiving path according to each received signal parameter of the first path and the second path, and the receiving path is the first path and the second path One of them, and the receiving path has the best received signal parameters.

In order to further understand the technology, methods and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be deepened and specific It is understood, however, the drawings are provided for reference and description only, and are not intended to limit the present invention.

1. 1’‧‧‧ Signal Quality Improvement System

21, 22‧‧‧ antenna

3‧‧‧antenna switching circuit

41, 42‧‧‧band switching circuits

51, 52‧‧‧ Duplexer

61, 62‧‧‧ Filter

71, 72, 73, 74, 71 ’, 72’ ‧‧‧ receive path selection circuit

8, 8’‧‧‧ RF Transceiver Circuit

9‧‧‧ fundamental frequency control circuit

10‧‧‧Voltage Regulator

11, 11’‧‧‧ control circuit

111, 112, 113, 114, 111 ’, 112’‧‧‧ switching circuits

121, 122, 123, 124, 125, 126, 127, 128, 121 ’, 122’, 123 ’, 124’ ‧‧‧ low noise amplifier

131, 132, 133, 134, 135, 136, 137, 138, 131 ’, 132’, 133 ’, 134’‧‧‧ paths

FIG. 1 is a schematic diagram of a system for improving received signal quality according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a system for improving received signal quality according to another embodiment of the present invention.

Various exemplary embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some exemplary embodiments are shown. However, the inventive concept may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers always indicate similar components.

It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements or signals, etc., these elements or signals should not be limited by these terms. These terms are used to distinguish one element from another, or a signal from another signal. In addition, as used herein, the term "or" may include, as appropriate, all combinations of any one or more of the associated listed items.

FIG. 1 is a schematic diagram of a system for improving received signal quality according to an embodiment of the present invention. The system 1 for improving the received signal quality of the present invention includes antennas 21 and 22, an antenna switching circuit 3, a frequency band switching circuit 41 and 42, a duplexer 51 and 52, filters 61 and 62, a receiving path selection circuit 71 to 74, The voltage regulator 10 and the control circuit 11. The duplexers 51 and 52 support the first frequency band B1 and the second frequency band B2, respectively, and the filters 61 and 62 support the first frequency band B1 and the second frequency band B2, respectively. The control circuit 11 includes a radio frequency transmission circuit 8 and a fundamental frequency control circuit 9. The receiving path selection circuits 71 to 74 include switching circuits 111 to 114 and low noise amplifiers 121 to 128. The antennas 21 and 22 are connected to the antenna switching circuit 3. The antenna switching circuit 3 is connected to the frequency band switching circuits 41 and 42. The band switching circuit 41 is connected to the duplexers 51 and 52, and the band switching circuit 42 is connected to the filters 61 and 62. The frequency band switching circuit 41 can switch the duplexers 51 and 52 to determine an operation frequency band. The frequency band switching circuit 42 can switch the filters 61 and 62 to determine an operating frequency band. The duplexers 51 and 52 are connected to the reception path selection circuits 71 and 72, respectively. The filters 61 and 62 are connected to the reception path selection circuits 73 and 74, respectively. The reception path selection circuits 71 to 74 are connected to the control circuit 11. The radio frequency transmission circuit 8 is connected to the fundamental frequency control circuit 9. The control circuit 11 is connected to a voltage regulator 10. The voltage regulator 10 is connected to low noise amplifiers 121 to 128. Further, the duplexers 51 and 52 are connected to the switching circuits 111 and 112, the filters 61 and 62 are connected to the switching circuits 113 and 114, the switching circuit 111 is connected to the low noise amplifiers 121 and 122, and the switching circuit 112 is connected to the low noise amplifier 123 and 124, the switching circuit 113 is connected to the low noise amplifiers 125 and 126, and the switching circuit 114 is connected to the low noise amplifiers 127 and 128. The low noise amplifiers 121 and 122 are located on the paths 131 and 132, respectively. The low noise amplifiers 123 and 124 are located on the paths 133 and 134, respectively. Low noise amplifiers 125 and 126 are located on paths 135 and 136, respectively. Low noise amplifiers 127 and 128 are located on paths 137 and 138, respectively. It should be noted that if there is only a single path connected to the control circuit, and this path is located near the source of interference, such as near a high-frequency oscillator, the reception of this path The signal quality will be poor, so the present invention designs a multi-path architecture to solve the above problems. Different paths may have different trace lengths, widths, and positions on the circuit board. For example, if the circuit board has a multilayer board structure, different paths can be set on different layers of the circuit board. Therefore, different paths will correspond to different Receive signal parameters; In addition, the low noise amplifiers on each path are the same components, that is, low noise amplifiers with the same characteristics.

The paths 131 to 138 are connected between the antennas 21 and 22 and the ports of the RF transmitting circuit 8. For example, the path 131 includes an antenna switching circuit 3, a frequency band switching circuit 41, a duplexer 51, a switching circuit 111, and a low noise amplifier. 121; path 132 includes antenna switching circuit 3, band switching circuit 41, duplexer 51, switching circuit 111, low noise amplifier 122; path 133 includes antenna switching circuit 3, band switching circuit 41, and duplexer 52. Switching circuit 112, low noise amplifier 123; path 134 includes antenna switching circuit 3, frequency band switching circuit 41, duplexer 52, switching circuit 112, low noise amplifier 124; path 135 includes antenna switching circuit 3. Band switching circuit 42, filter 61, switching circuit 113, and low noise amplifier 125; path 136 includes antenna switching circuit 3, band switching circuit 42, filter 61, switching circuit 113, and low noise amplifier 126. Path 137 includes antenna switching circuit 3, band switching circuit 42, filter 62, switching circuit 114, and low noise amplifier 127. Path 138 includes antenna switching circuit 3, band switching circuit 42, Multiplexer 62, the switching circuit 114, a low noise amplifier 128; addition, all paths can be used with an antenna 21 or antenna 22 to form a receive path.

It is worth noting that the above embodiment is only an example. The number of paths can be increased or decreased according to the number of antennas and the number of ports of the RF transmitting circuit. The antenna switching circuit, frequency band switching circuit, duplexer, and filtering on the path The number of amplifiers, switching circuits, and low-noise amplifiers also increases or decreases depending on the number of paths. Those skilled in the art can design the number of antennas and the number of ports of the RF transmitting circuit according to the system specifications, and then increase or decrease the number of paths and antenna switching circuits, band switching circuits, duplexers, filters, and switching circuits on the paths. The number of low noise amplifiers is not limited to the above embodiments.

In an embodiment, when the system 1 for improving the received signal quality of the present invention uses an antenna 21, a duplexer 51, and a receiving path selection circuit 71 to receive a signal, the control circuit 11 controls the receiving path selection circuit 71 to obtain a path 131 and a path 132. The control circuit 11 determines a receiving path according to each receiving signal parameter of the path 131 and the path 132, and the receiving path is one of the path 131 and the path 132, and the receiving path has the best receiving signal parameter. .

In one embodiment, the system 1 for improving the received signal quality of the present invention uses an antenna 21, an antenna switching circuit 3, a band switching circuit 41, duplexers 51, 52, and a receiving path selection circuit 71, 72 to receive a signal when the control circuit receives the signal. 11 Control the receiving path selection circuits 71 and 72 to obtain the received signal parameters of the paths 131-134. The control circuit 11 determines the receiving path according to the received signal parameters of the paths 131-134, and this receiving path is one of the paths 131-134. One, and this receiving path has the best received signal parameters.

In one embodiment, the system 1 for improving the received signal quality of the present invention uses an antenna 21, an antenna switching circuit 3, a band switching circuit 41, 42, a duplexer 51, 52, a filter 61, and a receiving path selection circuit 71, 72. When receiving signals at 73 and 73, the control circuit 11 controls the receiving path selection circuits 71, 72, and 73 to obtain the parameters of the received signals of the paths 131-136. The control circuit 11 determines the receiving path according to the parameters of the received signals of the paths 131-136. The receiving path is one of paths 131-136, and this receiving path has the best received signal parameters.

In one embodiment, the system 1 for improving the received signal quality of the present invention uses an antenna 21, an antenna switching circuit 3, a band switching circuit 41, 42, a duplexer 51, 52, filters 61, 62, and a receiving path selection circuit 71. When receiving signals at 72, 73, 74, the control circuit 11 controls the receiving path selection circuits 71, 72, 73, 74 to obtain the parameters of the received signals of paths 131-138, and the control circuit 11 according to the parameters of the received signals of paths 131-138 Determine the receiving path, and this receiving path is one of paths 131-138, and this receiving path has the best received signal parameters.

In an embodiment, when the system 1 for improving the received signal quality of the present invention uses antennas 21 and 22, an antenna switching circuit 3, a duplexer 51, and a receiving path selection circuit 71 to receive a signal, the control circuit 11 controls the antenna switching circuit 3 to The antenna 21 or the antenna 22 is selected, and the control circuit 11 determines the receiving path according to the received signal parameters on the path 131 and the path 132 corresponding to the antenna 21 and the received signal parameters on the path 131 and the path 132 corresponding to the antenna 22, and this The receiving path 1 includes one of the antenna 21 and the antenna 22 and one of the path 131 and the path 132, and this receiving path has the best received signal parameters.

In one embodiment, the system 1 for improving the received signal quality of the present invention uses antennas 21 and 22, antenna switching circuit 3, band switching circuit 41, duplexers 51 and 52, and reception path selection circuits 71 and 72 to receive signals. The control circuit 11 controls the antenna switching circuit 3 to select the antenna 21 or the antenna 22 and the frequency band switching circuit 41 to switch the duplexer 51 and the duplexer 52. The control circuit 11 controls the antenna switching circuit 3, the frequency band switching circuit 41, and selection of the receiving path. The circuits 71 and 72 determine a receiving path, and the receiving path includes one of the antenna 21 and the antenna 22, one of the duplexer 51 and the duplexer 52, and one of the paths 131-134, and the receiving The path has the best received signal parameters.

In one embodiment, the system 1 for improving the received signal quality of the present invention uses antennas 21 and 22, antenna switching circuit 3, band switching circuits 41 and 42, duplexers 51 and 52, filters 61, and reception path selection circuit 71. When receiving signals at 72, 73, control circuit 11 controls antenna switching circuit 3 to select antenna 21 or antenna 22, and controls band switching circuits 41 and 42 to switch duplexer 51, duplexer 52, and filter 61. Control circuit 11 The antenna switching circuit 3, the frequency band switching circuits 41 and 42 and the receiving path selection circuits 71, 72, and 73 are controlled to determine a receiving path. The receiving path includes one of the antenna 21 and the antenna 22, the duplexer 51, and the duplexer. One of 52 and filter 61 and one of paths 131-136, and this receiving path has the best received signal parameters.

In one embodiment, the system 1 for improving the received signal quality of the present invention uses antennas 21 and 22, antenna switching circuit 3, band switching circuits 41 and 42, duplexers 51 and 52, filters 61 and 62, and reception path selection. When the circuits 71, 72, 73, and 74 receive signals, the control circuit 11 controls the antenna switching circuit 3 to select the antenna 21 or the antenna 22, and controls the frequency band switching circuits 41 and 42 to switch the duplexer 51, the duplexer 52, and the filter 61. And filter 62, the control circuit 11 controls the antenna switching circuit 3, the frequency band switching circuits 41, 42 and the receiving path selection circuits 71, 72, 73, 74 to determine the receiving path, and the receiving path includes one of the antenna 21 and the antenna 22 1. One of the duplexer 51, the duplexer 52, the filter 61 and the filter 62, and one of the paths 131-138, and this receiving path has the best received signal parameters.

The received signal parameter can be the signal-to-interference noise ratio (SINR) of the received signal on paths 131-138, the automatic gain control (AGC) parameter of the received signal on paths 131-138, or the received signal on paths 131-138. Signal-to-interference-noise ratio and automatic gain control parameters. It needs to be reminded that because the RF transmitting circuit 8 will transmit the received signal to the baseband control circuit 9 for further processing, and the automatic gain control (AGC) parameter is the baseband control circuit 9 The transmitted signal performs a gain adjustment value. It is worth noting that the signal-to-interference-noise ratio of the received signal and the gain of the automatic gain control parameter can be the product of the signal-to-interference-noise ratio and the automatic gain control parameter, and the total of 10 times the signal-to-interference-to-noise ratio and the automatic gain control parameter Sum, or the sum of the signal-to-interference-to-noise ratio and one-tenth of the automatic gain control parameters. In addition to the above-mentioned changes, those skilled in the art can obtain the received signal parameters of the received signal according to the mathematical functions of the coefficient of the received signal, the interference-to-noise ratio, and the coefficients of the automatic gain control parameters, four arithmetic operations, integration, and differentiation, etc. This is the limit.

In an example, in the system 1 for improving the received signal quality of the present invention, when the control circuit 11 selects the path 131 and the antenna 21 as the antenna and path of the received signal according to the received signal parameters of the received signals of the paths 131 to 138, the control circuit 11 will adjust the receiving path selection circuit 121 on the path 131 of the optimal receiving signal parameter to increase the power gain. For example, when the control circuit 11 selects the path 131 and the antenna 21 as antennas and paths for receiving signals, the control circuit 11 adjusts the operating voltage of the low-noise amplifier 121 on the path 131 through the voltage regulator 10 to increase the power gain. For example, the preset operating voltage of the low noise amplifier 121 is 3.3V, and the fundamental frequency control circuit 9 adjusts the operating voltage of the low noise amplifier 121 to 3.8V, so that the power gain of the low noise amplifier 121 can be increased by about 0.2 ~ 0.5dB to improve the quality of the received signal. It should be noted that those skilled in the art can adjust the voltage value of the low-noise amplifier by themselves according to system requirements, and the present invention is not limited thereto.

For example, the system 1 for improving the quality of a received signal according to the present invention receives signals using antennas 21 and 22, an antenna switching circuit 3, a duplexer 51, and a receiving path selection circuit 71. Assume that the band B1 transmission frequency (TX Frequency) of the band operating in Long Term Evolution (LTE) is 1920 ~ 1980MHz, and the band B1 reception frequency (RX Frequency) is 2110 ~ 2170MHz. The received signal parameter of the path is Yi = SINR * ｜ AGC ｜. The signal to interference noise ratio at antenna 21 and path 131 is 10dB and the automatic gain control parameter is -200; the signal to interference noise ratio at antenna 21 and path 132 is 20dB and the automatic gain control parameter is -250; at antenna 22 and The signal to interference noise ratio of path 131 is 15dB and the automatic gain control parameter is -130; the signal to interference noise ratio of antenna 22 and path 132 is 25dB and the automatic gain control parameter is -180; four of the received signals are received signals The parameters are 2000, 5000, 1950, 4500 (taken as absolute values). In this embodiment, the larger the absolute value of the signal-to-interference-to-noise ratio and the automatic gain control parameter is, the better the reception quality is. The received signal parameter of the signal to obtain the best received signal parameter (5000) is the antenna 21 and the path 132. Then the control circuit 11 will adjust the received path selection circuit 122 on the path 132 of the optimal received signal parameter to improve the power gain and Get better received signal quality.

FIG. 2 is a schematic diagram of a system for improving received signal quality according to another embodiment of the present invention. The difference between the received signal quality improvement system 1 'of this embodiment and the received signal quality improvement system 1 of the previous embodiment is that the number of receiving ports of the radio frequency transmitting circuit 8' is different and the number of receiving path selection circuits is different. Since the receiving port of the radio frequency transmitting circuit 8 'can support receiving adjacent frequency bands, so that adjacent receiving frequency bands can share one receiving port, the received signal quality improvement system 1' of this embodiment can reduce the number of receiving path selection circuits. Adjacent frequency bands are expressed as the center frequency of two adjacent frequency bands does not exceed 100MHz. For example, frequency band B1_PRx and frequency band B2_PRx are two adjacent frequency bands, frequency band B1_DRx and frequency band B2_DRx are two adjacent frequency bands, so that frequency band B1_PRx and frequency band B2_PRx can share one port B1 / B2_PRx, and frequency band B1_DRx and frequency band B2_DRx can share one connection port B1 / B2_DRx. Therefore, the received signal quality improvement system 1 'of this embodiment includes reception path selection circuits 71', 72 ', and paths 131' to 134 '. The receiving path selection circuit 71 'includes a switching circuit 111' and low-noise amplifiers 121 'and 122'. The receiving path selection circuit 72 'includes a switching circuit 112' and low-noise amplifiers 123 'and 124'. The received signal quality improvement performed by the received signal quality improvement system 1 'of this embodiment is similar to the received signal quality improvement performed by the received signal quality improvement system 1 of the previous embodiment, so it will not be repeated here.

In one embodiment, the system 1 'for improving the quality of received signals of the present invention uses antennas 21, 22, antenna switching circuit 3, duplexer 51, and receiving path selection circuit 71' to receive signals, and control circuit 11 'controls antenna switching The circuit 3 selects the antenna 21 or the antenna 22, and controls the reception signal parameters of the circuit 11 'on the path 131' and the path 132 'corresponding to the antenna 21 and the reception on the path 131' and the path 132 'corresponding to the antenna 22. The signal parameter determines the receiving path, and the receiving path includes one of the antenna 21 and the antenna 22 and one of the path 131 ′ and the path 132 ′, and the receiving path has the best receiving signal parameter.

In one embodiment, when the received signal quality improvement system 1 'of the present invention receives signals using antennas 21, 22, antenna switching circuit 3, band switching circuit 41, duplexers 51, 52, and receiving path selection circuit 71', The control circuit 11 'controls the antenna switching circuit 3 to select the antenna 21 or the antenna 22 and the frequency band switching circuit 41 to switch the duplexer 51 and the duplexer 52. The control circuit 11' controls the antenna switching circuit 3, the frequency band switching circuit 41, and the reception The path selection circuit 71 'determines a receiving path, and the receiving path includes one of the antenna 21 and the antenna 22, one of the duplexer 51 and the duplexer 52, and one of the path 131' and the path 132 ' , And this receiving path has the best received signal parameters.

In one embodiment, the system 1 'for improving the received signal quality of the present invention uses antennas 21 and 22, antenna switching circuit 3, band switching circuits 41 and 42, duplexers 51 and 52, filters 61 and 62, and a receiving path. When the selection circuits 71 ′ and 72 ′ receive signals, the control circuit 11 ′ controls the antenna switching circuit 3 to select the antenna 21 or the antenna 22 and the control band switching circuits 41 and 42 to switch the duplexer 51, the duplexer 52, and the filter 61. And filter 62, the control circuit 11 'controls the antenna switching circuit 3, the frequency band switching circuits 41 and 42, and the receiving path selection circuits 71' and 72 'to determine the receiving path, and the receiving path includes one of the antenna 21 and the antenna 22 , One of the duplexers 51, 52, the filters 61, 62, and one of the paths 131'-134 ', and this receiving path has the best received signal parameters.

It is worth noting that the system for improving the quality of the received signal determines the number of antennas, antenna switching circuits, frequency band switching circuits, duplexers, filters, and receiving path selection circuits according to design requirements, determines paths and antennas based on the best received signal parameters, and By adjusting the low noise amplifier on the path of the best received signal parameters, the power gain is improved and the received signal quality is better.

In summary, the system for improving the received signal quality provided by the present invention can select different paths to obtain better received signal parameters, and at the same time increase the power gain, so as to effectively improve the received signal quality.

The above descriptions are only the preferred and feasible embodiments of the present invention, and any equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

Claims (14)

A system for improving the quality of a received signal includes: a first antenna for receiving a signal; a first frequency band duplexer coupled to the first antenna; a first receiving path selection circuit connected to the first frequency band The duplexer provides a first path and a second path; a control circuit connected to the first path and the second path; a second antenna for receiving signals; and an antenna switching circuit connected to the first path An antenna and the second antenna, and the first frequency band duplexer; wherein the control circuit controls the first receiving path selection circuit to obtain each received signal parameter of the first path and the second path , The control circuit determines a receiving path according to each received signal parameter of the first path and the second path, the receiving path is one of the first path and the second path, and the receiving path has the best reception Signal parameters; and wherein the control circuit controls the antenna switching circuit to switch the first antenna and the second antenna, and the control circuit according to the first path and the second path corresponding to the first antenna Each received signal parameter and the first path corresponding to the second antenna and each received signal parameter on the second path determine the receiving path, one of the first antenna and the second antenna, and the One of the first path and the second path forms the receiving path, and the receiving path has an optimal received signal parameter. The system according to claim 1, further comprising: a first frequency band switching circuit connected between the antenna switching circuit and the first frequency band duplexer; and a second frequency band duplexer connected to the first frequency band A switching circuit and the first receiving path selection circuit; wherein the first frequency band switching circuit switches one of the first frequency band duplexer and the second frequency band duplexer, the first antenna and the second antenna; 1. One of the first frequency band duplexer and the second frequency band duplexer, and one of the first path and the second path forms the receiving path. The system according to claim 2, further comprising: a second frequency band switching circuit connected to the antenna switching circuit; a first frequency band filter connected to the second frequency band switching circuit; a second frequency band filter connected to the antenna A second frequency band switching circuit; and a second receiving path selection circuit connected to the first frequency band filter and the second frequency band filter, and configured to provide a third path and a fourth path to the control circuit; wherein, the A second frequency band switching circuit switches the first frequency band filter and the second frequency band filter. The control circuit controls the second receiving path selection circuit to obtain each received signal parameter of the third path and the fourth path. The control The circuit determines the receiving path according to each received signal parameter of the first, second, third and fourth paths, one of the first antenna and the second antenna, the first frequency band duplexer, the first A two-band duplexer, one of the first-band filter and the second-band filter, and one of the first, second, third, and fourth paths form the receiving path. The system according to claim 1, wherein the first receiving path selection circuit further comprises: a first switching circuit for switching the first path and the second path; a first low noise amplifier provided in the On a first path; and a second low-noise amplifier disposed on the second path. The system according to claim 1, further comprising: a voltage regulator connected to the control circuit for adjusting an operating voltage of the low-noise amplifier having the receiving path. The system according to claim 1, wherein the received signal quality of the first path and the second path is the automatic gain control (AGC) parameter. The system of claim 1, wherein the received signal quality of the first path and the second path is a function of a signal-to-interference-noise ratio (SINR) and a gain of an automatic gain control (AGC) parameter. A system for improving the quality of a received signal includes: a first antenna for receiving a signal; a first frequency band duplexer coupled to the first antenna; a first receiving path selection circuit connected to the first frequency band The duplexer provides a first path and a second path; a control circuit connected to the first path and the second path; a first frequency band switching circuit connected to the first frequency band duplexer; a second frequency band A duplexer connected to the first frequency band switching circuit; and a second receiving path selection circuit connected to the second frequency band duplexer to provide a third path and a fourth path; wherein the control circuit controls the first A receiving path selection circuit obtains each received signal parameter of the first path and the second path, the control circuit determines a receiving path according to each received signal parameter of the first path and the second path, and the receiving path is the One of the first path and the second path, and the receiving path has an optimal received signal parameter; wherein the control circuit is connected to the third path and the fourth path; wherein the control The control circuit controls the second receiving path selection circuit to obtain the received signal parameters of the third path and the fourth path, and the control circuit determines the received signal parameters according to the received signal parameters of the first, second, third, and fourth paths. A receiving path, the receiving path being one of the first, second, third, and fourth paths, and the receiving path having an optimal receiving signal parameter. The system according to claim 8, wherein the second receiving path selection circuit further includes: a second switching circuit for switching the third path and the fourth path; and a third low noise amplifier provided in the On the third path; and a fourth low-noise amplifier is disposed on the fourth path. The system according to claim 8, further comprising: a second frequency band switching circuit; a first frequency band filter connected to the second frequency band switching circuit; and a third receiving path selection circuit connected to the first frequency band filter. And used to provide a fifth path and a sixth path; wherein the control circuit is connected to the fifth path and the sixth path; wherein the control circuit controls the third receiving path selection circuit to obtain the fifth path and the For each received signal parameter of the sixth path, the control circuit determines the received path according to each received signal parameter of the first, second, third, fourth, fifth, and sixth paths, and the received path is the first, One of the second, third, fourth, fifth and sixth paths, and the receiving path has the best received signal parameters. The system according to claim 10, wherein the third receiving path selection circuit further includes: a third switching circuit for switching the fifth path and the sixth path; and a fifth low noise amplifier provided in the On the fifth path; and a sixth low-noise amplifier disposed on the sixth path. The system according to claim 10, further comprising: a second frequency band filter connected to the second frequency band switching circuit; and a fourth receiving path selection circuit connected to the second frequency band filter and used to provide a seventh path And an eighth path; wherein the control circuit is connected to the seventh path and the eighth path; wherein the control circuit controls the fourth receiving path selection circuit to obtain the receiving signals of the seventh path and the eighth path Parameter, the control circuit determines the receiving path according to each received signal parameter of the first, second, third, fourth, fifth, sixth, seventh, and eighth paths, and the receiving path is the first, One of the second, third, fourth, fifth, sixth, seventh and eighth paths, and the receiving path has the best received signal parameters. The system according to claim 12, wherein the fourth receiving path selection circuit further includes: a fourth switching circuit for switching the seventh path and the eighth path; and a seventh low noise amplifier provided in the On the seventh path; and an eighth low-noise amplifier is disposed on the eighth path. A system for improving the quality of a received signal includes: a first antenna for receiving a signal; a first frequency band duplexer coupled to the first antenna; a first receiving path selection circuit connected to the first frequency band The duplexer also provides a first path and a second path; a control circuit connecting the first path and the second path, wherein the control circuit controls the first receiving path selection circuit to obtain the first path and For each received signal parameter of the second path, the control circuit determines a received path according to the received signal parameter of the first path and the second path, and the received path is one of the first path and the second path. And the receiving path has the best received signal parameters; and the quality of each received signal of the first path and the second path is a signal to interference and noise ratio (SINR).